package com.nuaa.community.service;

import com.nuaa.community.util.RedisKeyUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.SessionCallback;
import org.springframework.stereotype.Service;

/**
 * ClassName: LikeService
 * Package: com.nuaa.community.service
 * Description:
 */
@Service
public class LikeService {

    @Autowired
    private RedisTemplate redisTemplate;

    /**
     * 如果第一次点赞就加入set，如果第二次则取消赞并从set中删去
     * @param userId 当前用户id
     * @param entityType 类型：帖子？评论
     * @param entityId 实体的id
     * @param entityUserId 实体的用户id
     */
    public void like(int userId, int entityType, int entityId, int entityUserId){
        redisTemplate.execute(new SessionCallback() {
            @Override
            public Object execute(RedisOperations operations) throws DataAccessException {
                String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);
                String userLikeKey = RedisKeyUtil.getUserLikeKey(entityUserId);
                Boolean isMember = operations.opsForSet().isMember(entityLikeKey, userId);
                operations.multi();
                if (isMember) {
                    operations.opsForSet().remove(entityLikeKey,userId);
                    operations.opsForValue().decrement(userLikeKey);
                } else {
                    operations.opsForSet().add(entityLikeKey,userId);
                    operations.opsForValue().increment(userLikeKey);
                }
                return operations.exec();
            }
        });
    }

    /**
     * 查询某实体点赞的数量
     * @param entityType
     * @param entityId
     * @return
     */
    public long findEntityLikeCount(int entityType, int entityId){
        String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);
        return redisTemplate.opsForSet().size(entityLikeKey);
    }

    /**
     * 查询某人对某实体的点赞状态
     * @param userId
     * @param entityType
     * @param entityId
     * @return 返回1表示已点赞，返回0则是未点赞
     */
    public int findEntityLikeStatus(int userId, int entityType, int entityId) {
        String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);
        return redisTemplate.opsForSet().isMember(entityLikeKey, userId) ? 1 : 0;
    }

    /**
     * 查询某个用户获得的赞
     * @param userId
     * @return
     */
    public int findUserLikeCount(int userId) {
        String userLikeKey = RedisKeyUtil.getUserLikeKey(userId);
        Integer count = (Integer) redisTemplate.opsForValue().get(userLikeKey);
        return count == null ? 0 : count.intValue();
    }
}
